With the Sequential order number plugin, you can create custom sequential order numbers for your orders.
The plugin allows having order date as a prefix for sequential order numbers. Insert the below given code-snippet into functions.php of active theme file.
You can specify the order date in any required format. In the above snippet, the date format specified is ‘d/m/Y’
Order number with a date prefix
Sequential order number with order date as prefix will be as shown below: